Probably the most important thing to check is to make sure that the wireless network is protected by using WPA2 Personal security and a non-dictionary password of random letters and numbers.
You can review the wireless settings as follows:
Open Macintosh HD > Applications > Utilities > AirPort Utility
Click on the AirPort Extreme icon, then click Edit in the small box that appears
Click the Wireless tab at the top of the next window
Here you can edit the name of the wireless network if you wish, check the wireless security setting....WPA2 Personal is recommended....and edit/change the wireless network password.
Since the Motorola SB6141 is a bridge mode cable modem, you would want the AirPort Extreme to be configured as a router to provide DHCP and NAT services.
You can confirm this by clicking the Network tab at the top of the screen, The setting for Router Mode should read DHCP and NAT
Click the Network Options button near the bottom of the screen to see the default settings for DHCP IP address assignments. By default, the AirPort Extreme will assign IP addresses that look like 10.0.1.x to clients that join the network either by wireless or wired Ethernet connections.
The range of 10.0.1.2 to 200 simply means that the AirPort will assign IP addresses for up to 200 devices, 50 of which can be wireless devices. There is really no reason to change this setting unless you simply want to.
You can click the other tabs at the top of the screen to poke around a bit and see other settings for the AirPort Extreme if you want.
To save any changes that you make, click the Update button at the lower right of the window and the AirPort Extreme will restart and display a green light in about 30 seconds.
